20325 Clock Reference Failure of GGCU over 24 Hours

Description

The current clock reference of the GGCU board is in unusable state for 24 hours.

Attribute

Alarm ID	Alarm Severity	Alarm Type
20325	Major	Fault

Parameters

ID	Name	Meaning
1	Subrack No.	Subrack No.
2	Slot No.	Slot No.
3	Cpu No.	CPU No.
4	Alarm Attribute	0=Normal, Alarms period are longer than the Transient Threshold. 1=Transient Count, The times and the period of the alarms whose periods are shorter than the Transient Threshold are summed up. If the sum result is longer than the Alarm Occurrence Period Threshold or Alarm Occurrence Times Threshold, an alarm so called Transient Count Alarm is triggered. Because Transient Count Alarm is based on accumulative result, the recovery of the alarm may occur at least one Summing Cycle later. The Summing Cycle can be query by MML "LST STATSLDWIN".

Impact on the System

If the alarm is reported by the active board, the service will not be affected once the switchover between the active and standby boards succeeds.
If the alarm is reported by the active board, the service will not be affected once the alarm is cleared within 24 hours when the switchover between the active and standby boards fails.
If the alarm is reported by the active board, the service will be affected once the alarm is not cleared within 24 hours when the switchover between the active and standby board fails.
If the alarm is reported by the standby board, the service will not be affected.

System Actions

Handling of the active board in the active/standby operation mode: Perform the switchover if the standby is ready for the operation.
Handling of the standby board in the active/standby operation mode: None.

Possible Causes

The input signal for the clock reference is lost.
The frequency offset for the input signal of the reference source is abnormal, that is, the frequency offset is greater than that being introduced.
The board is faulty.

Procedure

As the handling procedures vary for different clock reference, please specify the type of the clock reference in the clock reference table.
If the type of the faulty clock reference is 2 MHz or 2 MBPS:
1. Secure the clock cable of the GGCU that connects the clock source, and then check whether the alarm is cleared.
  Y => The alarm is cleared. The alarm handling is complete.
  
  N => The alarm persists. Go to b.
2. Replace the clock cable, and then check whether the alarm is cleared.
  Y => The alarm is cleared. The alarm handling is complete.
  
  N => The alarm persists. Go to c.
3. Check whether the frequency offset output from the clock source is normal by using relevant equipment.
  Y => The frequency offset is normal. Go to d.
  
  N => The frequency offset is abnormal. Go to e.
4. Replace the board, and then check whether the alarm is cleared.
  Y => The alarm is cleared. The alarm handling is complete.
  
  N => The alarm persists. Please contact Huawei Customer Service Center.
5. Check whether the clock source is of BITS clock.
  Y => Contact the the maintenance engineer concerning the BITS clock to solve the problem. The alarm handling is complete.
  
  N => The clock source is from the interface board of the BSC. Go to f.
6. The interface board that output the clock source is faulty. Clear the relevant fault, and then check whether the alarm is cleared.
  Y => The alarm is cleared. The alarm handling is complete.
  
  N => The alarm persists. Please contact Huawei Customer Service Center.
If the type of the faulty clock reference is 8 K:
1. Secure the GGCU and the interface board that output the clock source, and then check whether the alarm is cleared.
  Y => The alarm is cleared. The alarm handling is complete.
  
  N => The alarm persists. Go to b.
2. Check whether there are clock-related alarms with the interface board that output the clock source.
  Y => There are clock-related alarms. Go to c.
  
  N => There is no clock-related alarm. Go to d.
3. Clear the clock alarm of the interface board according to its relevant handling suggestions, and then check whether the alarm of the board is cleared.
  Y => The alarm is cleared. The alarm handling is complete.
  
  N => The alarm persists. Go to d.
4. Replace the faulty GGCU , and then check whether the alarm is cleared.
  Y => The alarm is cleared. The alarm handling is complete.
  
  N => The alarm persists. Please contact Huawei Customer Service Center.